BOSTON — Breathing in dust and fumes from different vapors, gases, and solvents that are common in the workplace may increase the risk of developing rheumatoid arthritis, a new study warns.
Rheumatoid arthritis (RA) is a chronic condition that causes autoimmune joint pain and inflammation, affecting up to one in a hundred people worldwide. Prior studies have found a link between cigarette smoking and rheumatoid arthritis risk, but there has been less evidence linking the condition to workplace fumes. Most people with a typical day job spend around eight hours in their office space daily, which can lead to significant exposure to various pollutants over time.
To examine this risk, researchers used data from the Swedish Epidemiological Investigation of RA that included 4,033 newly diagnosed people between 1996 and 2017. In the control group, there were 6,485 healthy people, matched for age and sex, who did not have arthritis. The study authors also collected job history information and used it to estimate individual exposure to 32 different airborne agents in the typical workplace. Participants received a Genetic Risk Score (GRS) dependent on whether they carry genes that may increase their chance of developing RA. Those who are positive for anti-citrullinated protein antibodies (ACPA) generally have a worse RA prognosis and suffer greater rates of joint damage.
The team found that almost three-quarters of those with rheumatoid arthritis testing positive (73%) and negative (72%) for ACPA were exposed to at least one of the workplace dusts or fumes compared with around 67 percent of those in the control group. Their analysis showed that exposure to the agents led to an increased risk of getting RA, and also that smoking and genetic predispositions make this even worse.
Which airborne particles present the greatest danger?
“Triple exposure” — which describes smoking, having a high GRS, and workplace exposure to pollutants — displayed a link to arthritis onset that was 16 to 68 times higher compared to “triple non-exposure.” Interestingly, researchers not only found that exposure to any of the agents increased the risk of developing ACPA positive RA by 25 percent, but that the number jumps to 40 percent in men. Upon studying the exposure duration, the team also found that exposures lasting between eight and 15 years had the strongest impact on health outcomes. Overall, men experienced more exposure to harmful agents than women over time.
Particularly, 17 of the 32 agents displayed a strongly connection to an increased risk in ACPA positive disease, including asbestos, diesel fumes, gasoline, carbon monoxide, and fungicides. Only quartz dust, asbestos, and detergents had a connection to ACPA negative disease.
Though this study is observational and can’t definitively link RA to workplace fumes, the team concludes that environmental factors should be a regular consideration in RA diagnoses.
“Occupational inhalable agents could act as important environmental triggers in RA development and interact with smoking and RA-risk genes, leading to excessive risk for ACPA-positive RA,” the researchers write in a media release.
The findings highlight major implications for RA prevention and onset.
“First, each occupational inhalable agent had a unique profile of the way it interacted with RA risk genes and with smoking. These unique interactions suggest that if the relationship between inhalable agents and RA is indeed causal, they may do so via distinct pathways,” explains Dr. Jeffrey Sparks, of Brigham and Women’s Hospital.
He and the team conclude that public health efforts should aim to tackle the leading factors linked to the disease.
“First, environmental health initiatives should reduce public exposure to ambient pollutants, including carbon monoxide and gasoline exhaust. Second, occupational health initiatives should mitigate occupational hazards, including detergents and asbestos. Third, public health initiatives should continue to reduce cigarette smoking,” Dr. Sparks concludes.
The findings are published in the journal Annals of the Rheumatic Diseases.